Compared to other clay minerals, how does the cation exchange capacity (CEC) of kaolinite generally rank?

✅Explanation:
Kaolinite is a type of clay mineral that typically has a low cation exchange capacity (CEC) compared to other clay minerals such as montmorillonite or illite. This is because kaolinite has a more stable, tightly bound structure with fewer sites for cations (positively charged ions) to attach. As a result, it is less effective at holding nutrients like calcium, magnesium, and potassium compared to clays with higher CEC.

• CEC Comparison:
-Kaolinite: Typically has a CEC in the range of 3-15 cmol (+) / kg (centimoles of positive charge per kilogram of clay).
-Montmorillonite: Known for its high CEC, often ranging from 80-150 cmol (+) / kg due to its extensive structure and high negative charge.
-Illite: Generally, falls between kaolinite and montmorillonite in terms of CEC, with a range of around 20-100 cmol (+) / kg.

🛑 Additional Information::
-Cation-exchange capacity is a measure of the total negative charges within the soil that adsorb plant nutrient cations such as calcium, magnesium, and potassium.
-It is a useful indicator of soil fertility.
-It is a property of soil that describes its capacity to supply nutrient cations to the soil solution for plant uptake.
-It is measured in milliequivalents per 100 grams of soil (meq/100g).
-Clay minerals are hydrous aluminium phyllosilicates sometimes with variable amounts of iron, magnesium, alkali metals, alkaline earth metals, and other cations found on or near some planetary surfaces.
-These are generally classified into three layer types based on the number and arrangement of tetrahedral and octahedral sheets in their basic structure.
-The layer types are 1:1 (Kaolinite), 2:1 (Vermiculite), and 2:1:1 (chlorite).